Pericarditis is inflammation of the sac that surrounds and protects the heart (pericardium). Pericarditis can cause an abnormal buildup of fluid between the pericardium and the heart (pericardial effusion).

Pericarditis often improves without causing any damage to the heart.

In most cases, the cause isn't known. It can be caused by a virus, a heart attack, or a chest injury. It also can be caused by other types of illness.

Symptoms of pericarditis include:

• Severe, sudden pain in the center or the left side of the chest that may spread to the neck, back, shoulders, or arms. Breathing deeply, moving, or lying down often makes the pain worse. Sitting up and leaning forward may relieve the pain.
• Mild fever.
• A general feeling of weakness or fatigue.

Treatment for pericarditis may include medicines to reduce inflammation and relieve pain and antibiotics if the cause is a bacterial infection. If there is any fluid buildup, it may be drained.